Hello,

I am writing this post because I have a problem with my DJI MINI 2. Everytime I am flying, I get a "low GPS signal" message, although I am in an open air place in my village. Moreover, I can't go more than 300/400 meters further than my starting point (while the DJI MINI 2 can theorically go until 10km). I don't understand why this issue is happening because, if I understand correctly, my telecommand is sending signal to a satellite and the satellite is sending signal to the drone. Therefore, I don't know understand how the distance between me and my drone can affect the transmission.

Anyone can help me solve the problem ? It's pretty annoying to be forced to stay this close to my position.

Thanks a lot in advance for the help,

Julien

"if I understand correctly, my telecommand is sending signal to a satellite and the satellite is sending signal to the drone."

Wow! Incorrect... your drone gets it's GPS directly from the satellites. The movement of your drone is controlled by signal from your transmitter to your drone...

Ssayer Posted at 2-6 07:24
"if I understand correctly, my telecommand is sending signal to a satellite and the satellite is sending signal to the drone."

Wow! Incorrect... your drone gets it's GPS directly from the satellites. The movement of your drone is controlled by signal from your transmitter to your drone...

Thanks for the reply !

Ok, it makes sense now. But do you know how I can improve the range of my drone ? 400m seems pretty low for a drone that is supposed to be able to fly up to 10km. If it could go to 4/5km I would not complain but 400 feels too little.
Is there any way to improve the range of the drone ?

Everytime I am flying, I get a "low GPS signal" message, although I am in an open air place in my village.
Perhaps there might be a problem with the drone.
If you have an unobstructed skyview the drone should have plenty of sats.

Moreover, I can't go more than 300/400 meters further than my starting point (while the DJI MINI 2 can theorically go until 10km).
Your drone can go much further, but only in an area where there is no interference from wifi etc.
Interference is common in urban areas and reduces the range.

if I understand correctly, my telecommand is sending signal to a satellite and the satellite is sending signal to the drone.
Your drone and controller send nothing to any satellites.
The drone receoves location data from satellites.

Therefore, I don't know understand how the distance between me and my drone can affect the transmission.
More interference = less range.

If you post flight data that might help understand your issue better.
Go to: https://www.phantomhelp.com/LogViewer/Upload/
... where you'll find instructions.
That will give a report you can post a link for the report here.
Or just post the .txt file.

Labroides Posted at 2-6 07:48
Everytime I am flying, I get a "low GPS signal" message, although I am in an open air place in my village.
Perhaps there might be a problem with the drone.
If you have an unobstructed skyview the drone should have plenty of sats.

Thanks for your detailed reply, I appreciate it !

Therefore, if I am in the nature the drone should be able to go very far ? And if I am in the nature but surrounded by obstacles (trees for example), does it interfere ?

I have downloaded DJI GO 4 right now to record my flight data, will provide it here after my next flight.

Thanks again

julien0901 Posted at 2-6 11:26
Thanks for your detailed reply, I appreciate it !

Therefore, if I am in the nature the drone should be able to go very far ? And if I am in the nature but surrounded by obstacles (trees for example), does it interfere ?

Be extremely careful with restricted areas in Belgium. The airspace is quite dense and the law rather strict.
Sometimes it's not a bad thing that the drone can only go 400m.

https://belgiandronefederation.be/fr/legislation
https://mobilit.belgium.be/nl/luchtvaart/vliegen-met/drones-uas

julien0901 Posted at 2-6 11:26
Thanks for your detailed reply, I appreciate it !

Therefore, if I am in the nature the drone should be able to go very far ? And if I am in the nature but surrounded by obstacles (trees for example), does it interfere ?

Your flight data is already recording using the DJI Fly App.  DJI Go 4 is not compatible with the Mini 2.

julien0901 Posted at 2-6 11:26
Thanks for your detailed reply, I appreciate it !

Therefore, if I am in the nature the drone should be able to go very far ? And if I am in the nature but surrounded by obstacles (trees for example), does it interfere ?

if I am in the nature but surrounded by obstacles (trees for example), does it interfere ?
Trees are full of water which blocks signal, but only if there are trees between your controller and the drone.
A few branches or just a tree or two, not so much.
But more trees = more signal blocking.

I have downloaded DJI GO 4 right now to record my flight data, will provide it here after my next flight.
No need as DJI Go is the correct app for your drone and it works the same way.

Hi, julien0901. Thank you for notifying us about this concern. We're sorry about the difficulties you're experiencing. GPS may not work properly due to interference with the compass. Minimize interference by avoiding areas with metal, radio transmission towers, high-voltage lines, substations, and high-power electromagnetic interference equipment. If there is an error with the compass, calibrate it and try testing again. Additionally, we sent you a PM to further discuss your concern. Kindly check at your earliest convenience. Have a nice day.

DJI Tony Posted at 2-6 22:15
Hi, julien0901. Thank you for notifying us about this concern. We're sorry about the difficulties you're experiencing. GPS may not work properly due to interference with the compass. Minimize interference by avoiding areas with metal, radio transmission towers, high-voltage lines, substations, and high-power electromagnetic interference equipment. If there is an error with the compass, calibrate it and try testing again. Additionally, we sent you a PM to further discuss your concern. Kindly check at your earliest convenience. Have a nice day.

This "advice" is bogus.
His issue has nothing to do with the compass.
If it did, he'd have other obvious issues and would have mentioned them.

DJI Tony Posted at 2-6 22:15
Hi, julien0901. Thank you for notifying us about this concern. We're sorry about the difficulties you're experiencing. GPS may not work properly due to interference with the compass. Minimize interference by avoiding areas with metal, radio transmission towers, high-voltage lines, substations, and high-power electromagnetic interference equipment. If there is an error with the compass, calibrate it and try testing again. Additionally, we sent you a PM to further discuss your concern. Kindly check at your earliest convenience. Have a nice day.

I also have a little trouble understanding how the calibration of a magnetic compass can interfere with a GNSS receiver.

Unless it is a GNSS compass with two antennas like the M300, but which does not require calibration. And given the size of the mini it's probably impossible.

Transmissions tower, High voltage lines, electromagnetic interference in general ok why not. They can generate harmonics which "jam" the GNSS signal. But metal surfaces...

Is it a purely software limitation that makes the relationship between compass and accuracy of the receiver?

Is it possible to have a slightly more technical explanation? This isn't the first time this answer has been phrased like this, we need to understand.

The other things to consider here is that the original poster is new to drones.  There is a possibility that he was flying using the controller only versus having the app?  

Thank you all for your answers !

To answer the last message, no I was not using the controller only, I was using the app.
The weather is pretty ... here these days, when it clears up I will do another flight and provide my flight data. But reading the comments, I think the problem is that my house is on a hill surrounded by trees, so I think this is the issue blocking the transmission. I have also tried mostly flying in my village, which if I understand well, can cause issues too.

I will make a try in a complete nature environment, without being surrounded by trees and will keep you informed.

julien0901 Posted at 2-10 04:23
Thank you all for your answers !

To answer the last message, no I was not using the controller only, I was using the app.

If you go back to my first reply here, follow the instructions and post your flight data it might help you to get proper answers.

LV_Forestry Posted at 2-6 23:32
I also have a little trouble understanding how the calibration of a magnetic compass can interfere with a GNSS receiver.

Unless it is a GNSS compass with two antennas like the M300, but which does not require calibration. And given the size of the mini it's probably impossible.

Transmissions tower, High voltage lines, electromagnetic interference in general ok why not. They can generate harmonics which "jam" the GNSS signal.
None of those have been shown to have any effect on GPS reception.
Suggesting they might is spreading misinformation.


But metal surfaces...
They say metal, but they mean steel.
He's referring to generating a yaw error which can cause the drone to ignore GPS data.

Is it possible to have a slightly more technical explanation? This isn't the first time this answer has been phrased like this, we need to understand.
You won't get that from this source because it's not on the script they work from.

Labroides Posted at 2-10 05:56
If you go back to my first reply here, follow the instructions and post your flight data it might help you to get proper answers.

I have extracted the txt files, where can I put them ? I can only upload pictures in my answer here

julien0901 Posted at 2-10 09:52
I have extracted the txt files, where can I put them ? I can only upload pictures in my answer here

You could upload to dropbox or similar and post a link or I gave instructions for another method.

Labroides Posted at 2-10 06:00
Transmissions tower, High voltage lines, electromagnetic interference in general ok why not. They can generate harmonics which "jam" the GNSS signal.
None of those have been shown to have any effect on GPS reception.
Suggesting they might is spreading misinformation.

A GNSS antenna is sensitive to almost everything. At different levels. One tree is enough.
It is real life experience.

I have a camera equipped with a microcomputer with a modem. When starting the computer, the modem tries to connect to a network for several minutes. During this period the GNSS signal is jammed. As soon as I turn off the computer it comes back.  The next time I use it I will try to think of making a video for you.

All electromagnetic signals generate harmonics. The closer you are to the source, the more powerful they are in terms of jamming.

I found a web page that explains the phenomenon well:
https://www.amateur-radio-wiki.net/harmonics/

Then, you divide the frequency of the GNSS signals and this will give you which source produces harmonics on these frequencies.

Modern GSM transmitters are "clean" enough not to "vomit" on all frequencies.
It's not always the case. I invite you to try flying your drone next to an amateur radio transmission tower.  

It's not disinformation, it's more science and a lot of precautions.

I agree with you, when the compass is not optimal, it ignores GNSS data. Would this explain why the OP only sees very few satellites? I look forward to your analysis of his flight data. We will know a little more at that time.

Ah yes the script of the moderators, I had forgotten. Although lately I find that there are more and more technical answers. Instead of apologize's standard copy paste.

LV_Forestry Posted at 2-10 14:23
A GNSS antenna is sensitive to almost everything. At different levels. One tree is enough.
It is real life experience.

Transmissions tower, High voltage lines, electromagnetic interference in general ok why not. They can generate harmonics which "jam" the GNSS signal.
In real-world drone flying, people aren't going to lose GPS signal because of any of those.
It might be possible in certain circumstances, like flying within 1 or 2 metres of some of them, but it's nothing that is ever going to affect almost all DJI users.

Because DJI spread this misinformation about hypothetical extreme cases, it's common for new users to believe that flying within a kilometre of those things will cause all kinds of malfunction.

Labroides Posted at 2-10 14:37
Transmissions tower, High voltage lines, electromagnetic interference in general ok why not. They can generate harmonics which "jam" the GNSS signal.
In real-world drone flying, people aren't going to lose GPS signal because of any of those.
It might be possible in certain circumstances, like flying within 1 or 2 metres of some of them, but it's nothing that is ever going to affect almost all DJI users.

I totally agree with this point of view.

Labroides Posted at 2-10 13:36
You could upload to dropbox or similar and post a link or I gave instructions for another method.

Thanks, you can find the flight notes from one of my flight here : https://www.dropbox.com/s/o2pjpyapaszk91m/DJIFlightRecord_2023-01-28_%5B14-39-37%5D.txt?dl=0

julien0901 Posted at 2-11 08:33
Thanks, you can find the flight notes from one of my flight here : https://www.dropbox.com/s/o2pjpyapaszk91m/DJIFlightRecord_2023-01-28_%5B14-39-37%5D.txt?dl=0

Hi Messi,

Had a look at your log.

Start your flight with zero satellites!
After 21 seconds in flight HomePoint was set, so not at your take-off point, well about 9 meters away *
* if the landing spot = takeoff spot.
Rest of the flight more than enough satellites and good reception.
So that is not the problem.

Many messages :

• Le signal de la radiocommande est peut-. Orientez la radiocommande vers lappareil et ajuster les antennes pour une puissance de signal optimale ou volez. Signal faible. Ajuster les antennes.
• Orientez la radiocommande vers lappareil et ajuster les antennes pour une puissance de signal optimale ou volez. Signal faible. Ajuster les antennes. Le signal de la radiocommande est peut-.
  

Lost signal for 2.9 seconds at 3m55s  at distance of 918 meter away.

See my chart of your data, orange line is where all the messages about the signal RC<>Drone was not that good.
In the other charts you see the up and down link values in colour.

If you position was surrounded by trees than that is probably the issue for 'bad' connection.

BTW  see how inaccurate the first LatLon postions are, while only a few GPS satellites are receiving, See the orange line in chart4.That is why it is so important to wait for a GPS lock before takeoff.


cheers
JJB  [ chart by FRAP ; the 'best' software for flightlog analysis ]

You could also try 5.8Ghz in the Transmission section of the app. That will help with wifi interference, but not with trees and range.

JJB* Posted at 2-11 10:44
Hi Messi,

Had a look at your log.

Thanks a lot for your detailed analysis, I appreciate it a lot !

It seems a bit complicated for me, but I think I understand the main points of it. So, to resume :
* I should wait a GPS lock before takeoff. How do I perform that ? Just turn the drone on and wait until the "low GPS signal" disappears ?
* I should position myself in a location not surrounded by trees. If I understand well, all the stuff that is between my command and the drone will contribute to bad transmission. Therefore, the "perfect" location to pilot the drone would be on a hill with a clear view ?
I think this would be difficult to achieve because the area were I live is very hilly and there are lots of forests, but I will try to find a good spot and see if I can go further with the drone.

Again, thanks a lot for taking so much time to help me

Zoooom Posted at 2-11 17:34
You could also try 5.8Ghz in the Transmission section of the app. That will help with wifi interference, but not with trees and range.

Thanks for the suggestion, I will try it during my next flight

julien0901 Posted at 2-12 02:46
Thanks a lot for your detailed analysis, I appreciate it a lot !

It seems a bit complicated for me, but I think I understand the main points of it. So, to resume :

Hi Julien,

About the GPS lock, check the top right GPS icon in the FlyApp.

RED = too low number of satellites for a GPS lock
AMBER = GPS lock, but too low number of sats to set a HomePoint.
WHITE = GPS lock + HomePoint has been set.

Use the compass/attitude indicator to aim your RC towards the drone. Little arrow will turn green when RC is pointing to the drone.
Indeed the best position for a RC is on top of a hill, good radio line of sight to your drone. Such position is not always possible, realize that radio signals needs good line of sight when flying far. So flying far in general do not fly too low heights.....




cheers
JJB  [ by FRAP ; the 'best' software for flightlog analysis ]

JJB* Posted at 2-12 05:09
Hi Julien,

About the GPS lock, check the top right GPS icon in the FlyApp.

Hi JJB,

Thanks, I will take all of that in consideration for my next flight, and will provide you feedback on how it goes !

Thanks again and have a nice week-end